Walter a



W. A. BOCKIUS.

LAP FOR CYLINDERS.

APPLlcATloN FILED Nov.a. 191s.

x 1,318,531. Patented 0G11. 14,1919.

UNTED sTArEs "PATENT cierren.

'WALTER A. BOCKIUS, 0F WILMETTE, ILLINOIS.

LAP FOR CYLINDERS.

To all whom t may concern:

Be it known that I, WALTER A. BooKIUs, a citizen of the United States, and a resident of Wilmette, in the county of Cook and State of Illinois, have invented certain new and usefulv Improvements in Laps for Cylinders, of which the following is a full,

an improved lap in which the use of spring is dis pressed bars' or a separate s rin pensed with and in which a cylindrical body is utilized to apply the abrasive, so that substantially the entire peripheral surface of the body will be simultaneously active when it is operated in a cylinder.

A further object of the invention is to i provide a lap which is simple in construction and can be produced at a low cost. The invention consists in the several novel features hereinafter set forth and more particularly deined'by claims at the conclusion hereof.

In the drawings: Figure 1 is a side elevation ofthe improved lap. Fig. 2 is a longitudinal section,y the shank bemg shown in elevation. 3 is a plan, the s ank being shown in sectlon. Fig. 4 is a development of the periphery of the body of the rap showin the grooves therein' for the abrading or po ishing material.

f v'The improved lap comprises a one-piece body comprising a rim 5, `a hub 6, an arm 7 connecting the rim and the hub, anda strengthening rib 8, al1 integrally formed of a casting of suitable metal. A shankpQ-for rotatin the-Nap is removabl `connected to the hu 6' b `a screw-threa ed portion 10. The up er end of the shank is tapered, as at 11, so t at it may, be secured into the chuck of a drill press or` other suitable machine for rotation totlie shank. A shoul- I i' der 12 o the'll'shank 'liiits a ainst the upper end of the hub 6. This s oulder and the screw-thread adapt the shank for connec tion to any ofa series of laps of different Specification' of Letters Patent. 'i

Patented oet. '14, 1919.

Application led November 8, 1916. 'Serial No. 180,118.

diameters. In practice, it is customary to have an equipment consisting of different sizes of bodies for bores of different diameters and by providing a detachable connection between the hub 6 and the shank 9, the laps vmay be readily and speedily interchanged for cylinders of different diameters.

In making the one-piece body, it is cast somewhat larger than the bore of the cylinder which itis adapted to polish or grind and then a section of the rim is slitted or y cut away longitudinally, as indicated at 14 in Fig. 3, adjacent one side ofthe connecting arm 7. .After the rim has been thus cut, it is placed in a clamp whereb it is .contracted to the limits permitted i y the slit and then'turned in a lathe to the exact diameter desired for a given diameter of the cylinder. When the clamps have been removed, the elasticit of the rim will expand it to open the s ot 14 and as a result it will form a body which is resilient and slightly larger in diameter than the diameter of the cylinder which it is adapted ,to polish or abrade. 'When the rim is forced 1nto a cylinder of the size for which it is adapted, the rim will exert a substantially uniform yielding ressure against all portions of the cyllndhr wall around the rim. The slit 14 is cut through the rim adjacent 3, so that the resilient portion of the rim will be drawn around the cylinder instead of being` pushed,'because a pushing action might tend to'operate thelapunevenlyor bind in the cylinder. In practice, the shank 9 is rotated at the desired speed to cause the lap to rotate in the cylinderor other Jpart to be polished or abraded. Helicoidal grooves 15 and 16 extend from the edges of the slit 14 around the peri hery and op,-

positeiy helicoidal grooves l and 18 are orme in the periphery of the rim and cross the rooves 15 .and 16. In practice,

grease wit suitable grinding powder or material therein is smeared-on the periphery of the rim and into the grooves before the lap is lowered into the cylinder 19. The helicoidal crossed grooves serve to distribute the grease andabrasive during rotation ofthe lap;v

The invention exemplifies a lap in which spring bars are dispensed with anl which is formed of one piece and with a resilient 4'that side of the arm 7 which is the front side during rotation, as indicated .in Fig.

llii

rim, the entire peripheral area of which is operative in the cylinder during the operation of the lap. As a result, a cylinder can be quickly ground or polished. By forming the lap in. the manner described, it can be produced at a low cost. A Series of laps inay be interchangeably connected to the shank.

The invention is not to be understood as restricted to the details set forth, since these may be modied Within the scope of the appended claims, without departing from the spirit and scope of the invention.

Having thus described the invention, what l claim as nevi and desire to secure by Letters Patent, is:

l. lin a la the combination of a substantially cylindrical rim which is longitudinally split at one point and a rigid support for one portion ofthe rim and whereby it may be rotated, the rim being inhermieles.

ently resilient and unsupported except by said support so that the remaining portions thereof Will be free to be contracted'by the work.

2. in a lap, the combination of a rim which is longitudinally split, a hub and a, support between the hub and one point of the rim, said hub, support and one portion of the rim being integral, 'the rim being resilient and unsupported except by said support so that the remaining portions thereof will be free to be contracted by the Work.

3. ln a lap, the combination of a hub, an

i arin and a rini which is longitudinally split at one point, the hub and rim being integral and the rim being rigidly supported at the arin and being inherently resilient so that portions remote from the arm are movable relatively to the portion directly connected to the arm.

WALTER A. BOCKTUS. 

